Merge pull request 'feat(#496): enforce canonical state comment validation before posting' (#497) from feat/issue-496-canonical-comment-validator into master

docs/llm-workflow-runbooks.md

@@ -887,6 +887,55 @@ touched release state names the exact tag/commit and why. Design debates
 belong in **discussion/RFC issues** (e.g. #100 `profiles.json v2`) — comment
 on the issue, create no branches/PRs, and end the comment with this handoff.
 
+## Canonical comment validation (#496)
+
+Workflow-changing issue/PR/review comments must carry durable next-action
+state. Casual discussion is still allowed.
+
+The MCP server runs `canonical_comment_validator.assess_canonical_comment`
+**before** posting through:
+
+- `gitea_create_issue_comment`
+- `gitea_submit_pr_review` / `gitea_dry_run_pr_review` (non-empty review bodies)
+- `gitea_reconcile_already_landed_pr` when `post_comment=True`
+- internal structured comment helpers (machine lease/heartbeat markers stay exempt)
+
+Detection examples:
+
+- **Allowed:** `Thanks, I will check this.`
+- **Rejected:** `Blocked, author should fix.` (workflow trigger without canonical fields)
+
+When validation fails, the tool returns `canonical_comment_validation` with
+`allowed: false`, `missing_fields`, `vague_fields`, `correction_message`, and
+`suggested_template`. **No Gitea API call is made.**
+
+Minimum workflow comment fields:
+
+```text
+STATE:
+WHO_IS_NEXT:
+NEXT_ACTION:
+NEXT_PROMPT:
+WHY:
+```
+
+`WHO_IS_NEXT` must be one of: `controller`, `author`, `reviewer`, `merger`,
+`reconciler`, `user`.
+
+Issue comments also require `RELATED_PRS`, `BLOCKERS`, and `VALIDATION` when
+they mention PR work. PR comments/reviews also require `ISSUE`, `HEAD_SHA`,
+`REVIEW_STATUS`, `MERGE_READY`, `BLOCKERS`, and `VALIDATION`.
+
+Special states:
+
+- `STATE: blocked` — `BLOCKERS` must name an explicit unblock condition.
+- `STATE: superseded` — requires `CANONICAL_ITEM` and `SUPERSEDED_ITEM`.
+- `STATE: ready-to-merge` — requires approval proof and head SHA in
+  `HEAD_SHA`, `REVIEW_STATUS`, `MERGE_READY`, or `VALIDATION`.
+
+Final reports must not claim a comment was posted when
+`canonical_comment_validation.allowed` is false (#496 AC14).
+
 ## Fail-closed behavior
 
 Before any mutating action the workflow verifies identity, active profile,